Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
  • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
  • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
  • G06K19/08—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means
  • G06K19/10—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means at least one kind of marking being used for authentication, e.g. of credit or identity cards
  • G06K19/12—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means at least one kind of marking being used for authentication, e.g. of credit or identity cards the marking being sensed by magnetic means

Definitions

• This invention relates to a method of identifying a data carrier, and particularly, though not exclusively, to reading codes stored in a security element attached to a card or document as a permanent pattern of a magnetic property detectable, for example, as a variation of remanent magnetisation along the element.
• a data carrier of this kind is described in GB-A- 1,331,604 in which in spaced regions of an element anisotropic magnetic particles are dispersed and fixedly aligned in a binder along a preset direction, whilst in remaining regions the particles are not so aligned or are aligned along a substantially different preset direction.
• This arrangement is commonly described as a magnetic "watermark” or as forming a "permanent magnetic structure” since unlike conventional magnetic recordings the pattern of remanent magnetisation revealed by uniaxially magnetising or “developing” the document can be restored by re-magnetisation even after erasure by the application of an a.c. erase field, for example.
• a magnetic "watermark” is particularly well suited to recording data in digital form since each alignment direction may be assigned a different significance i.e. a binary "ONE” or a binary "ZERO".
• a security element may conveniently be prepared as a single "watermarked” tape comprising strings of binary coded numbers (usually grouped in characters) which provide a security feature when cut from the tape and applied to a support to form a document or card.
• strings of binary coded numbers usually grouped in characters
• each string of numbers is separated by a marker or "sentinel” comprising a unique sequence of bits which itself never appears in the security data. For this reason the "sentinel" can always be identified so that by reference to its position on the document the bits chosen to represent the security data (a particular set of characters appearing on the document, for example) can always be recovered.
• a method of identifying a data carrier carrying data in the form of a plurality of rational numbers in a sequence, successive numbers having a marker between them comprising:- a) measuring the distance from a fixed point on the data carrier to a given part of a marker, b) dividing this distance by the distance between corresponding given parts of successive markers, thereby obtaining a rational number (x), and c) adding or subtracting this rational number (x) to (from) the number in the sequence adjacent the said marker in a given direction, thereby obtaining a further rational number which is capable of identifying the data carrier uniquely.
• the data carrier comprises a document or card carrying a security element having data encoded thereon as a permanent pattern of a detectable magnetic property, and the fixed point on the data carrier is constituted by an edge of the document or card. This simplifies the measurement of the distance in part a) of the above mentioned method.
• Figure 1 shows a length of magnetically encoded tape constituting a security element
• Figure 2 shows a data carrier in the form of a card
• Figure 3 shows a block diagram of a method according to the invention.
• FIG 1 a length of "WATERMARK” tape (10) obtainable from Thorn Secure Science Ltd, Swindon, England is shown schematically.
• the tape has a permanently magnetised structure.
• the data encoded thereon comprises markers known as start sentinels (1 1), having identification numbers (12, 13, 14) in the form of binary digits therebetween.
• the identification numbers are in a sequence comprising the integers arranged in ascending magnitude, for example 300, 301, 302, 303 etc..
• Figure 2 shows a piece of the tape of Figure 1 attached to a credit card 15.
• the distance between the edge of the card 16 and the start of the first marker or start sentinel (x) is denoted in Figure 2 by the reference numeral 17.
• the distance between the edge of the card 16 and the start of the second marker or start sentinel is denoted in Figure 2 by the reference numeral 18.
• the inventors have realised that by treating the identification number not as a sequence of integers but as a continuously varying quantity it is possible to remove the ambiguity inherent in other methods of identifying adjoining parts of the tape.
• Each identification number is deemed to start at the beginning of the marker or start sentinel to the left of the identification number in Figure 2.
• the measuring means comprises a magnetic read head which looks for the first marker or start sentinel. As well as reading the number which follows the marker, the measuring means measures the distance (x, 17) between the edge of the card 16 and the beginning of the first marker. This analogue distance is then expressed as a fraction of the marker pitch by dividing x by the distance between the markers (i.e. 18 - 17).
• the data on cards is generally set down at a constant pitch and is designed to be self clocking.
• Block 1 denotes measuring the distance from a fixed point on the data carrier to a given part of a marker
• block 2 denotes dividing this distance by the distance between corresponding given parts of successive markers, thereby obtaining a rational number (x)
• block 3 denotes adding or subtracting this rational number (x) to (from) the number in the sequence adjacent the said marker in a given direction, thereby obtaining a further rational number which is capable of identifying the data carrier uniquely.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Theoretical Computer Science (AREA)
• Signal Processing For Digital Recording And Reproducing (AREA)
• Editing Of Facsimile Originals (AREA)
• Financial Or Insurance-Related Operations Such As Payment And Settlement (AREA)
• Radar Systems Or Details Thereof (AREA)
• Management, Administration, Business Operations System, And Electronic Commerce (AREA)
• Credit Cards Or The Like (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Publications (1)

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ID=10787530

Family Applications (1)

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Families Citing this family (17)

Citations (3)

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• 1996
  • 1996-01-25 GB GB9601463A patent/GB2309568B/en not_active Revoked
• 1997
  • 1997-01-14 US US09/117,336 patent/US6179211B1/en not_active Expired - Lifetime
  • 1997-01-14 AU AU13930/97A patent/AU710207B2/en not_active Ceased
  • 1997-01-14 WO PCT/GB1997/000101 patent/WO1997027565A1/en active IP Right Grant
  • 1997-01-14 PL PL97328238A patent/PL182808B1/pl not_active IP Right Cessation
  • 1997-01-14 EP EP97900348A patent/EP0876656B1/en not_active Expired - Lifetime
  • 1997-01-14 DE DE69700654T patent/DE69700654T2/de not_active Expired - Fee Related
  • 1997-01-14 KR KR10-1998-0705735A patent/KR100446055B1/ko not_active IP Right Cessation
  • 1997-01-14 CN CN97192607A patent/CN1101968C/zh not_active Expired - Lifetime
  • 1997-01-14 JP JP9526631A patent/JP2000504127A/ja not_active Ceased
  • 1997-01-14 CA CA002244216A patent/CA2244216C/en not_active Expired - Fee Related
  • 1997-01-14 UA UA98074079A patent/UA35650C2/uk unknown
  • 1997-01-23 ZA ZA9700562A patent/ZA97562B/xx unknown
  • 1997-01-23 MY MYPI97000264A patent/MY131799A/en unknown
  • 1997-05-03 TW TW086105912A patent/TW351793B/zh not_active IP Right Cessation
• 2000
  • 2000-09-28 CN CNB001288628A patent/CN1147820C/zh not_active Expired - Fee Related
• 2002
  • 2002-04-30 HK HK02103209.9A patent/HK1041546B/zh not_active IP Right Cessation

Patent Citations (3)

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